There are 2 types of risks to bitcoin or any crypto in the big picture: Fast and slow.
FAST: In the blink of an eye, something happens on the network that shows the system is compromised. Someone reverses transactions, creates coins out of nowhere, steals coins…
SLOW: Over time a problem will grow and get worse. It’ll get slower, too expensive to use, will emit too many new coins…
When/if bitcoin segwit splits, there will be 2 chains. The old chain will have 8 years of live testing against the possibility of Fast risks. The bitcoin network survived through years of use by hackers, computer geniuses and criminals- unscathed- all while the network was exponentially smaller, less understood, less scrutinized and vulnerable.
Bitcoin clearly can’t be hacked as is, they’d have done it by now.
In time, I believe solutions to any and all slow risks will be diminished- either through tech, or a multi-coin universe. Slow risks will be overcome, Fast risks have been tested against.
The segwit chain offers advantages toward Slow risks, but will be completely untested on a live system against Fast risks.
Just a simple analysis from someone who doesn’t code. I know Bitcoin can’t be hacked, its been proven. Segwit chain? Maybe in 8 more years I’ll be ready to invest.